As we promised in the Giant Killers blog, on Monday we begin detailed breakdowns of all the first-round games with GK implications.

Now that we all have brackets in hand, it's time for a detailed look at how our Giant Killers statistical model sees NCAA tournament matchups. We'll go region by region, and, as we did in 2011, we will sort potential upsets into four categories: Best Bets, Worth a Long Look, Not Completely Crazy and Stay Away. These names should be pretty self-explanatory -- Best Bets have a decent chance to win outright and Stay Aways are likely to lose no matter what. But we can't tell you exactly how to fill out your brackets, because that depends on how heavily your particular pool rewards upsets. The more points you score when underdogs win, the more you should be willing to pick high-risk teams.

In case you've forgotten, a Giant Killer is a team that beats an opponent seeded at least five spots better and doesn't come from a BCS conference. Other teams -- Gonzaga, Butler, BYU, Temple and Xavier -- are excluded because of their historical success. (Check out our methodology for a full explanation.) Our model generates statistical ratings that compare potential Giant Killers to past Davids as well as all Giants to the Goliaths who were slain. Those ratings enable us to predict the chances of an upset in each matchup.

We now move on to the West, where we find our best bet for an early upset.

MIDWEST REGION

To see the most likely upset picks in the West region and get access to all of Insider's NCAA tournament tips and tools, sign up today.

Peter Keating is a senior writer at ESPN The Magazine, where he covers investigative and statistical subjects. He started writing "The Biz," a column looking at sports business from the fan's point of view, in 1999. He also coordinates the Magazine's annual "Ultimate Standings" project, which ranks all pro franchises according to how much they give back to fans. His work on concussions in football has earned awards from the Deadline Club, the New York Press Club and the Center for the Study of Sport in Society.